Accelerated bridge construction chapter 6 rapid bridge insertions following failures

Accelerated bridge construction chapter 6 rapid bridge insertions following failures Accelerated bridge construction chapter 6 rapid bridge insertions following failures Accelerated bridge construction chapter 6 rapid bridge insertions following failures Accelerated bridge construction chapter 6 rapid bridge insertions following failures Accelerated bridge construction chapter 6 rapid bridge insertions following failures

CHAPTER Rapid Bridge Insertions Following Failures 6.1 Introduction All of us cross bridges every day We may only see a parapet railing deck slab or sign structures and light poles But there is more to a bridge than meets the eye The bearings and girders may be hidden in addition to the substructure foundations Bridges span gaps in terrain or other earth features such as gorges formed due to river valleys and natural cavities in topography Transportation bridges are an essential part of a network of highways and provide continuity to their use for rapid travel If a bridge is shut down, it adversely affects the sick going to hospitals, children going to schools, and others missing important plane flights and the train departures, thereby adversely affecting essential progress in commerce and industry It is time that new technology for alternative designs related to rapid construction is introduced A glossary of accelerated bridge construction (ABC) terminology applicable to all the chapters is listed for ready reference in Appendix ABC This rapid construction technology is already being promoted by a number of federal and state organizations such as the Federal Highway Administration (FHWA) (reference PowerPoint presentation by Benjamin Beerman, Incharge, FHWA Every Day Counts Program), New Jersey (reference Mohiuddin Khan and State Bridge Engineer Richard Dunne’s paper at ABC Conference in Baltimore, 2007) Reference seminars organized by the author at Temple University, the FHWA, and by Florida International University (FIU) are listed in Appendix This chapter covers the following topics relating to bridge failure and rapid construction techniques:   Numerous incidences of recurring damage and failures in the conventional system of design and construction are demonstrated in this chapter, requiring a review of the design and construction philosophy An alternate ABC system (to that currently in vogue) with prefabrication and preassembly is proposed to overcome the difficulties The difficulties are in transportation to the site and the availability of high-capacity cranes The use of prefabricated girders is on the rise and the conventional system has been modified to a partial ABC system It is expected that due to the increased popularity and many advantages of ABC system, the partial ABC system will be a good place to start, leading eventually toward full ABC The percentage of bridge projects using ABC will eventually increase to over 80% if not to 100% Accelerated Bridge Construction http://dx.doi.org/10.1016/B978-0-12-407224-4.00006-X Copyright © 2015 Elsevier Inc All rights reserved 257 258 CHAPTER 6  Rapid Bridge Insertions Following Failures 6.1.1  Construction duration and impacts on maintenance and protection of traffic (MPT) MPT requirements were addressed in Chapter Inconvenience to the public will continue as long as the reconstruction is not complete MPT will depend upon the following:   Staging of construction with no lane closure - Shoulder width or the sidewalk may be used with added widths obtained from converting 12 ft to 10 ft Staging with one or more lanes closed Detour Bridge shut down for traffic during construction duration   Given infinite time, any structure can be built, replaced, or repaired The highway agencies are more interested in fixing a bridge in a finite time Their budgets are allocated from year to year and need to be used up within the given year and not linger on or overlap with the ongoing fresh allocations Hence the purchases of bridges or sales of demolished bridges are for a limited time only (Figure 6.1) According to Mammoet Europe B.V., the on-site construction of bridges and flyovers is often impossible, so complex, or has such a large impact on traffic flows, that off-site construction is required These large and heavy elements need to be brought in and installed in a timely manner that minimizes interference with construction activities Close coordination between these different activities is essential Thorough analyses and engineering help define the optimum dimensions and weights of the modules, taking the capacity of lifting and transport equipment into account Route surveys are conducted to understand and counter any possible bottlenecks along the way that may restrict the size of modules or have an impact on the timing of the project Also, knowledge of oversized load restrictions and regulatory issues helps determine the most efficient approach Modular construction challenges require a modern fleet of equipment, enabling lifting, transport, skidding, and push-up of modules of different dimensions and weights for ABC FIGURE 6.1 Any gap even in a wide river can be bridged with the right plan and construction equipment (Reference Mammoet Europe B.V.) 6.2  Bridge failures can be prevented by asset management methods of ABC 259 6.1.2  Maintenance of old bridges We are used to maintaining our cars on a regular basis, replacing essential parts every few years and replacing an old car every 10–15 years The same approach applies to bridges We replace the concrete or asphalt topping or the deck slab itself every 10–15 years Most bridge superstructures are replaced every 50–75 years with or without the substructure Bridges are subjected to repeated wear and tear from heavier trucks and from extreme events such as flood and earthquakes Maintenance requires timely rehabilitation, repair, and retrofit There is an old saying that “a stitch in time saves nine.” If a bridge is neglected, an emergency replacement may result, and that is where ABC is particularly useful Life cycle costs are likely to be higher than the initial investment It may be more economical and easier to design a new bridge than to maintain the same bridge over its remaining life Not counting railway and transit bridges, the three types of roads on which bridges are located are:   • Interstate: Due to heavy average daily traffic (ADT), not even a single lane can be shut down for maintenance Already, there are traffic jams during rush hour Time loss is a colossal waste at national scale • Collector: A lane can be closed for a short duration with nighttime work using ABC • Local: When ADT is low, ABC is not essential, and for small spans modular bridges can be used.  6.2  Bridge failures can be prevented by asset management methods of ABC By analyzing the repetitive nature of bridge failures that involve conventional construction, it may be possible to reduce the number of failures with ABC Scour and soil erosion with foundations not protected by scour countermeasures are responsible for the majority of failures The Dee Bridge failure in 1847 is one example The major causes of bridge failures can be summed up as follows:   • Foundation scour and soil erosion: Examples are bridge failures such as the collapse of Ovilla Road Bridge over a flooded creek in Ovilla, Ellis County, Texas and Route 46 Peckman’s River Bridge after Hurricane Floyd in New Jersey The Peckman’s Bridge replacement was designed by the author • Corrosion of steel girders concrete deck and deck concrete cracking: An example is the I-95 curved girder bridge • Earthquake: Bridge failures in California • Overload and excessive magnitude of live load: Numerous older bridges • Excessive wind on suspension bridges without deck stiffening: Tacoma Narrows Bridge • Failure due to fatigue: Numerous railway bridges • Collision from trucks due to limited vertical under clearance: An example is the North Jersey Bridge • Collision from ships due to fog and heavy rain: An example is collapse of the Sunshine Skyway Bridge in Florida • Fire: An example is the I-95 Bridge in northesast Philadelphia due to the burning of tires below   Failures seem to occur worldwide for a variety of reasons The inventory of bridges worldwide is in the millions and is gradually growing with the construction of new highways 260 CHAPTER 6  Rapid Bridge Insertions Following Failures In the United States alone, there are 600,000 bridges These are subjected to constant wear and tear and to natural disasters Avoiding failures and keeping highways functional is the top priority of all highway agencies and they have access to the taxpayers’ money to that The useful life of a bridge seldom exceeds 100 years with maintenance Inventories of bridge failures are being maintained by owners as well as the media, as they are public knowledge According to a conservative estimate, even if 1% of the total number of bridges is estimated as deficient, 6000 bridges in the United States need to be fixed in the form of repairs, retrofit, and widening and replacement Increased use is being made of the innovations in design and construction technology For effective maintenance, inspection procedures are changing rapidly by way of remote health monitoring and use of sensors for crack detection In addition to the American Association of State Highway and Transportation Officials (AASHTO) and FHWA, the National Transportation Safety Board (NTSB) is responsible for overseeing bridge failures However, unexpected failures like that of a steel truss bridge on I-35 West in Minneapolis in 2004 could be avoided Similar truss bridges are standing elsewhere in the United States A single-span nonredundant design is less safe as compared to a redundant design The bridge that failed in Minneapolis was built in 1967 but had an alarming ADT rate of 144,000 An inquiry revealed that the gusset plates were under-designed and failed under the additional construction loads An in-depth survey of modern bridge failures by the author, based on available information, has revealed various modes of failure of highway structures and bridges, many of which are elaborated upon in this chapter The overall objective of the study of such failures is to improve design codes and construction specifications and to reduce the duration of construction through techniques such as ABC 6.2.1  Failure modes Failure modes are different for steel, concrete, and timber bridges For steel composite bridges, plastic hinges form at the midspan or at the ends of cover plates Tension yielding occurs in the bottom flange and in the web to the underside of the top flange accompanied by cracking at the bottom surface of the slab In prestressed concrete beams, collapse may occur due to breakage of the strands These failures can be avoided by simultaneous adoption of ABC with modern design techniques A fascinating aspect of these failures is their regularity, a display of the mode of failure, which needs to be recognized and avoided by design and maintenance It will be easier to avoid major failures when occurring approximately every 30 years: 1847, 1879, 1907 (Quebec Bridge failure), 1940, and c.1970 A Sibly and Walker study (1977) is referred to as a point for discussion Fitting the trend, two bridge failures are considered consistent by H Petroski (1993) Petroski points to anecdotal evidence that suggests the theory has predictive merit Also, the managing director of Brady Heywood, Sean Brady, has looked at the technical and human aspects of this unfortunate trend Refer to http://bradyheywood.com au/uploads/129.pdf It may be pointed out that many failures that occur during construction or demolition not get reported The present total number of bridges located in the U.S highway system is extremely high Lack of adequate maintenance and accidental failure can cause failures to occur sooner than 30 years, as recent failures in Minnesota and Washington State have shown ABC prefabrication methods with better quality control should help in reducing the frequency of failures 6.3  Inspection and rating procedures as a starting point for maintenance 261 6.2.2  Importance of deck stiffening in suspension cable bridges The importance of deck stiffness in suspension bridge design was recognized as far back as the 1850s As a consequence, Roebling’s generation utilized stiffening trusses and auxiliary ties to ensure deck stability, elements that are evident on the Brooklyn Bridge today The gradual elimination of stiffening trusses and ties culminated in their absence from the Tacoma Narrows Bridge Failure ensued, and the Tacoma Narrows Bridge was rebuilt with stiffening trusses included These failures provide some insight into negligence and also the importance of innovative structural design 6.3  Inspection and rating procedures as a starting point for maintenance Monitoring of the structural health of bridges is required to identify any potential issues Bridges that are fracture-critical or scour-critical are vulnerable to failure The frequency of the two-year inspection timetable has been reduced to one year in such cases In the case of extreme events such as floods and earthquakes, around-the-clock inspection may be necessary A theoretical criterion such as sufficiency rating is used to identify deficiencies The objectives of inspection are as follows:   • Asset management • Safety inspection and testing • Structural evaluation • Identification of deficiencies • Suggestion of repair, retrofit, and/or rehabilitation solutions • Prevention of failures   In the United States, the bridge management system (BMS) is formulated by the following agencies:   • AASHTO • FHWA • Each state where the bridges are located   An analytical tool is needed at the network level, rather than at the individual project level It will use a systematic procedure for optimizing bridge inspection analysis data This is achieved by the use of the Pontis System described earlier in Chapter Ratings were defined in Chapter under “­Management System for Bridges NBIS.” 6.3.1  Sufficiency rating Sufficiency rating (SR) is a score that indicates a bridge’s sufficiency to stay in service by meeting traffic demands and safety needs It is a measure of the relative safety of bridges SR is a percentage from (worst) to 100 (best) based on an FHWA formula that includes four factors:   • Structural adequacy and safety, S1 (Max 55%) • Serviceability for modern use, and functional obsolescence, S2 (Max 30%) • Essentiality for public use, S3 (Max 15%) • Special reductions, S4 (Max 13%)   262 CHAPTER 6  Rapid Bridge Insertions Following Failures SR = S1 + S2 + S3 − S4 If the SR value is < 20%, the bridges are considered deficient and need to be fixed However, FHWA defines a structural evaluation score “requiring high priority of replacement.” While a bad rating does not necessarily mean failure is imminent, when combined with high traffic volumes represented by traffic count and ADT, it signals possible trouble for a bridge Based on visual inspections and low sufficiency ratings, those bridges that are found to be vulnerable to structural failure seem to require rehabilitation or replacement 6.3.2  FHWA condition rating The general structural health or condition of the bridge components can be defined by the physical observed field condition, defined as the condition rating The NBIS Condition Rating uses the numbering system given in Table 6.1 6.3.3  Visual inspection versus structural health monitoring An alternate to visual inspection is to use a robotic system that can inspect bridges more frequently Sensors, optical instrumentation, and digital cameras are some of the recent developments Cracks, corrosion, and deformations can be measured by modern image processing (infrared imaging devices) and pattern recognition techniques A detailed survey of nondestructive health monitoring methods was carried out by Jahanshahi and colleagues at the University of Southern California (2009) 6.3.4  Contract documents After the project funding is approved, the consultant and contractor’s team will be selected with the conventional system or the ABC design-build system through bids For greater detail, the Design Build Institute of America (DBIA) may be consulted Table 6.1  NBIS Condition Ratings Rating Number Relative Rating N Failed Imminent failure Critical Serious Poor Fair Satisfactory Good Very good Excellent Not applicable 6.3  Inspection and rating procedures as a starting point for maintenance 263 The set of minimum documents covering the technical, administrative, and legal aspects of conventional construction will consist of the following:   • Contract drawings • Estimate of quantities • Construction specifications • Special provisions • Construction schedule using bar charts or a Primavera network (showing milestones and the duration of each activity on the critical path)   Contract drawings are prepared to the required scale in CAD They are used for construction and are required to show maintenance and protection of traffic (MPT) and erection details such as locations of cranes during lifting These are not acceptable unless signed and sealed by a registered professional engineer in that state 6.3.5  Legal signing of contracts In general, notarized, signed agreements between the owner and the contractor and between the owner and the consultant are normally required The consultant’s expertise should be in civil engineering, structural engineering, or bridge engineering For ABC contracts, agreements need to be signed between the contractor and the consultant The subcontractors who get hired by the contractor will normally be approved by the owner After the contractor is selected, an attorney representing the owner will collect all the necessary signatures and notarize the legal document as necessary The contract language will be in keeping with the federal and state laws, especially since they are responsible for providing the huge project funds For example, there will be provisions for hiring minorities and women as an equal opportunity employer Payments will be made according to accounting rules and are subject to audits The format for the above legal documents may change for ABC, depending upon the state requirements and the transportation agency within the state For example, turnpike authority and river bridge commissions may deviate from the general format of other construction contracts as they may have developed their own construction specifications 6.3.6  Shop drawings for structural components All “shop drawings” normally required for fabrication will be in conformity with the contract drawings and will be prepared by the manufacturing company after the contract is awarded The nitty-gritty details such as small additional holes or the location of lifting points of the component need to be shown and duly approved by the consultant It is important that communication is maintained by weekly meetings at the site or the owner’s office There should be no secrets, and the right hand should know what the left hand is doing before it is too late and an accident happens 6.3.7  Rehabilitation reports required for both conventional and ABC systems A number of bridges located on the same highway can be conveniently included in the same report, since the rehabilitation can be performed simultaneously Efforts will be made to use the same 264 CHAPTER 6  Rapid Bridge Insertions Following Failures equipment and labor The rehabilitation report should be comprehensive and often the following reports need to be included (the exact practice may vary from state to state and from project to project; see Textbook by Mohiuddin Khan, 2010 Repair of Highway Bridge Structures, McGraw-Hill):   • Field survey, topography, and drainage reports • Visual inspection reports • Underwater inspection reports • Structural evaluation reports • Rehabilitation or replacement options • Geotechnical reports • H and H (hydrology and hydraulic) reports • Scour countermeasures report • Seismic retrofit reports • Estimate of quantities • Cost estimates based on approved unit prices • Special considerations or any other memorandums from the relevant highway agency   Each report will be site-specific and unique There are often alternate options Usually, cost will be the deciding factor for selecting the alternate option 6.3.8  Implementation of drawings During construction, if the original field data has changed (for example, the excavation shows a different type of soil than delineated in the geotechnical report, etc.), the drawings need to be immediately modified by the consultant The procedure is to use a formal design change notice (DCN) with the approval of the owner Due diligence is required by the contractor, who is required to point out any discrepancy in the construction drawings in a timely manner Usually the contractor generates a request for information (RFI), which is documented The designer after investigation will clarify the query in writing without causing delay to the tight schedule As an incentive, if the contractor finishes the job ahead of schedule, he or she is entitled to a bonus To meet or expedite the construction, a full-time “resident engineer” is posted by the consultant at the job site The resident engineer performs quality assurance/quality control (QA/QC) of daily work at the site, certifies completed work for payment, and prepares a weekly progress report and submits it to the project manager at the head office with a copy to the owner Some owners may insist that the resident engineer follows the designer for any DCN due to the engineer’s detailed knowledge of the design criteria, project data, and background of the construction drawings, which may run into several dozens, if not hundreds, in number 6.4  Probability of failure and risk management 6.4.1  Hazard, vulnerability, and risk A hazard can be defined as “a condition or changing set of circumstances that presents a potential for property damage, structural failure and injury.” Vulnerability analysis shows susceptibility to loss from hazard It is opposite of resilience Risk defines the likelihood of an event and its consequences 6.4  Probability of failure and risk management 265 6.4.2  Hazards and sources of hazards By hazard analysis we identify threats to transportation and its users Hazards can be the result of natural causes or man-made causes Negligence, poor communication, and lack of teamwork or knowledge leading to planning and design errors can contribute to the creation of hazards Both the application of preventive methods using preparedness methods and the provision of adequate cures using disaster management methods are needed after a hazard For controlling hazards and preventing failures, it is important to recognize hazards, their probability of occurrence, and their past history The principles of hazard control are:   • Identification and recognition • Defining preparedness and selecting preventive actions • Assigning responsibility for implementing preventive actions • Providing means for measuring effectiveness and adjusting them • Preparing a safety checklist related to the project   The goal in safety engineering is to prevent the fulfillment of Murphy’s Law According to the famous Murphy’s Law, “whatever can possibly go wrong, will.” Sometimes, the factor of safety used in design loads or material strengths may not be sufficient They may also result from insufficient, delayed, or improper maintenance and repair In practice, the huge investment of funding for the infrastructure is safeguarded by taking out liability insurance against unforeseen circumstances and human errors The failures or damage can happen in the short term or in the long term For example, by federal law, you cannot drive a vehicle without insurance, even though unsafe driving resulting in damage or an injury may not be your fault In bridge construction, the failure may happen after, say, 20 years, when the contractors who built the bridge no longer exist But insurance claims will be applicable and will be paid by the insurance company Even if the insurance company is not there, there will be a guarantee from the government or the banking industry to pay the claims, so that the taxpayer is not penalized The three considerations related to failure are the above-defined hazard, vulnerability, and risk In the United States, the federal Occupational Safety and Health Administration (OSHA) oversee failures or injuries during construction and develops and enforces related regulations The three most frequently cited OSHA violations (2003) are construction related, as shown in Table 6.2 It will be noted that with ABC, use of scaffolding can be avoided The numbers are approximate as all construction accidents may not get reported Most accidents or violations result in loss of life, equipment, or property The owner may not pay for the related losses as per the provisions of the signed contract The contractor may bear the loss or the liability insurance may approve the claims Table 6.2  OSHA Construction-Related Citations of Violations Leading to Damage and Injury Rank Topic Number of Citations Remarks Method of Hazard Control Scaffolding Hazard communication Fall and injury protection 8682 7318 5680 Construction related Construction related Construction related Use prefabrication Use design-build management Implement OSHA regulations 266 CHAPTER 6  Rapid Bridge Insertions Following Failures There are a set of priorities in construction that will be helpful:   • Elimination of hazards • Reducing the level of hazard • Providing structural redundancy • Installation of sensors and monitor stress levels • Issuing warnings • Introducing safety procedures in design • Offering training to personnel   A good reference on this topic is Safety and Health for Engineers, by Roger L Brauer (2006) The hazard control models proposed by Brauer in his book are the four M’s: man, media, machine, and management The nine general factors in the goal accomplishment model can be applied to ABC by making each factor specific These are listed in Table 6.3 Bridge engineering also complies with the general factors in Table 6.3 in its goal accomplishment model It consists of preparing structural drawings, devising the construction process, project management, manufacturing components, selecting equipment, using self-propelled modular transporters (SPMTs) and high-capacity cranes, ensuring environmental protection, and reducing hazards that cause failures 6.4.3  Risk analysis of river bridge failure Risk is characterized as low, medium, high, or unacceptable When risk is high, advanced risk assessment is required and risk management procedures should be implemented Bridges located on rivers are subject to higher hazard assessment than those located at, for example, an intersection, due to factors such as:   • River instability • Extraneous factors causing morphological change • Fluvial hydraulics in the vicinity of the river crossing • Structural integrity of the bridge   Table 6.3  Factors for Goal Accomplishment and their Applications to ABC Factors for Goal Accomplishments Applications People Activities Equipment Place Environment Management Regulatory organization Time Cost Knowledge and training, culture and attitudes Engineering decisions and actions taken Special vehicles, crane and construction equipment Highway, bridge, and waterway Floods, earthquakes, and natural hazards Role performed by the owner, consultant, or contractor Highway planning and bridge design and construction specifications Duration of contract (which cannot linger on forever) Funds available, initial cost, and long-term maintenance costs 294 CHAPTER 6  Rapid Bridge Insertions Following Failures 6.9.1  Important features addressed by FHWA Mobility impact time is the duration of the traffic flow of the transportation network that is reduced due to on-site construction activities This includes the reduction or removal of the following items:   • Maintenance of traffic • Materials • Equipment • Labor   Future of ABC: According to the FHWA, 40% of bridges were built over 40 years ago with a 50-year design life 25% require rehabilitation, repair, or replacement Lessons learned:   • Team composition: involve contractors with ABC experience during the design process • Plan for unexpected problems: have extra equipment on standby • Do not be afraid to think outside the box   Site constraints:   • Local ordinances and permits • Construction easements • Right-of-way   Utilities site constraints • Temporary or permanent relocations • Wetlands   Constructability/design:   • Meet with contractors to develop potential ABC techniques • Allow ABC techniques to be flexible in project specifications • Study transportation routes for bridge components and equipment to site   Material procurement:   • Components of ABC • Geotechnical solutions • Soil-bearing capacity for heavy lifts • Foundations and walls • Advance pile driving   Abutment solutions:   • Tie-back anchors • Abutment saw cutting • Abutment modifications   Prefabricated bridge elements and systems:   • Abutment caps   6.10  Recent progress made with successful completion of ABC 295 FIGURE 6.9 Axles of an SMPT their magnitude can be higher than HS-20 axle loads Precast bridge seat loading:   • Deck panels: concrete and steel   Structural placement:   • Skidding (roll-in) • Use of SPMT: self-propelled modular transports (Figure 6.9) Chapter 3, Section 3.2 describes types of SPMT There is no standard length but more axles can be added as required • Peak bending moments need to be checked so that the bridge components are not overstressed 6.10  Recent progress made with successful completion of ABC Chapter described examples of successful completion of prefabricated projects in a number of states Projects completed by Kraemer Company are listed here Within a relative short period, progress has been made in the implementation of ABC Successful examples are shown in Table 6.23 and those completed by Kraemer in Table 6.24 in the United States due to efforts from FHWA and others   NICTD Train Crossing the New Structure   Friday, November 3, 2000: Start roll-in mobilization Sunday, November 5, 2000: Finished railroad opens for normal operation   • Detailed planning   Checklist for go/no go meeting Detailed outage schedule   296 CHAPTER 6  Rapid Bridge Insertions Following Failures Table 6.23  Recent Successful Project Examples using ABC Name of Bridge Application ABC Details 4500 South over I-215 (2007) Accelerated bridge construction using SPMTs Riverdale Road over I-84 (2008) Accelerated bridge construction using precast and ­prefabricated elements Payson deck replacements (2009) Accelerated bridge construction using precast, prefabricated elements Accelerated bridge construction using transverse sliding • Bridge needed immediate replacement due to rapid deterioration of bridge supports • New bridge was constructed adjacent to the structure • New bridge was moved using SPMTs during one weekend closure • Existing bridge spans were removed using SPMTs • Self-compacting backfill used to accommodate tight work area • 90% precast elements • Innovative noncomposite deck • Innovative strategy for phasing • Match-cast elements at on-site casting yard • Noncomposite deck panels • Longitudinally post-tensioned ABC strategy for phasing • Phase I: Construct outside bridge quarters • Phase II: Move traffic to outside, construct inside two quarters • Phase III: Tie phases together and open entire bridge • Accelerated phasing • Longitudinally post-tensioned • Predemo work I-80 over Echo Dam Road, Utah (2010) I-80 bridges over 2300 East, Salt Lake City, Utah (2009) I-15 south, Layton Interchange (2010) Accelerated bridge construction using transverse sliding I-15 CORE, Sam White Bridge (2011) Accelerated bridge construction using jacking/launching Accelerated bridge construction using jacking/launching • Replacement of EB and WB I-80 over Echo Rd • Bridges replaced using horizontal skidding of the new bridge superstructures onto new abutments constructed under existing bridges while they remained in service Final bridge placement in 7 h Overnight detour on the ramps during slide • Abutments and approach slabs on temporary supports • Bridge slid onto new abutments and sleeper slabs Daytime closures allowed on cross-street Approach slabs construction with bridge • Replacement of EB and WB I-80 bridges • Similar method as Echo Road bridges • Vertical clearance challenge required bridge jacking • Single-point urban interchange (SPUI) over I-15 • Constructed each span on temporary steel frame supports above 12 feet of surcharge on approach embankments • Surcharge was excavated from beneath the spans and they were lowered onto rail system Two temporary bents used during launch process and then removed Each bridge span was moved within 6-h nighttime closures Bridge constructed on temporary supports Surcharge removed underneath • Jacked down onto slide rails • Span launched out over I-15 during night closure • First two-span bridge moved in North America • Night closure • Four SPMT rows 6.10  Recent progress made with successful completion of ABC 297 Table 6.24  Kraemer’s Recent Successful Project Examples Using ABC Name of Bridge Application CNR Rainy River Bridge replacement (float-in) Baudette, Minnesota Client: Canadian National Railway CPR Bascule Bridge replacement (float-in) RTD Fast Track West Corridor light rail transit over 6th Avenue (roll-in) US-6 Clear Creek Canyon Bridge rehabilitation (full depth precast deck panels, Figure 6.10) Powers North design-build (precast deck panels and abutments) Page Avenue tied arch bridge (float-in) ABC Details The Rainy River Bridge replacement project included the replacement of five existing bridge spans, including a swing span with six new 176-foot through truss spans Four trusses were erected on temporary platforms and floated into place and two trusses were erected on temporary bents Once the new trusses were built and in place on the temporary bents adjacent to the existing bridge, the old spans were floated out and the new spans were rolled into place during three, two-day switch-outs La Crosse, Wisconsin Client: The Bascule Bridge replacement project involved the Canadian Pacific Railway replacement of a 100-year-old swing span over the Black River in La Crosse, Wisconsin The 307-foot structure was replaced with a 147-foot single-leaf bascule span weighing 500 tons and two 104-foot through-plate girder spans Span replacements were completed in sections by floating-in and floating-out or rolling-in and rolling-out The new bascule span was operational for marine craft less than 48 h after the bridge was opened to rail traffic Lakewood, Colorado The RTD over 6th Avenue project was constructed as Regional Transportation part of nine structures for the West Corridor, the first leg Department of a multicorridor rapid transit expansion in the Denver metro area, extending from Denver to Golden, Colorado This ballasted light-rail bridge carries double track service over the 6th Avenue Freeway and is the signature bridge of the West Corridor The basket-handled arch was constructed on falsework “off-line” and rolled into place utilizing pushing rams in the rear and heavy transports in front of the structure in a single 36-h period Clear Creek Canyon The US-6 project was the fast-track reconstruction of the (between Denver, Black superstructure, rehabilitation of the substructure, and full Hawk, and Central City, CO) depth deck replacement of three bridges located in Clear Client: Colorado DepartCreek Canyon on US-6 in 12 days ment of Transportation Colorado Springs, Colorado Client: Colorado Department of Transportation St Louis, Missouri Client: Missouri Department of Transportation The Powers North design-build project was the accelerated construction of six bridges and one mile of divided four-lane highway on SH 21 at Briargate Parkway, Union Boulevard, and Pine creek opening the road to traffic in 118 calendar days Construction of twin 17-span bridges across the Missouri River as part of the Page Avenue Extension Project relieving congestion on I-70 in St Louis, Missouri Kraemer constructed two, 600-foot-long tied arches for the main bridge spans To expedite construction, each tied arch was floated into place above the Missouri River’s navigational channel on a falsework tower custom designed by Kraemer 298 CHAPTER 6  Rapid Bridge Insertions Following Failures FIGURE 6.10 Example of full-depth deck panels • Mobilization   Start: Roll-in mobilization at a.m Friday, November 3, 2000   • Demolition operations Bridge jacking   Friday: Removal of the west panel of the existing truss bridge Saturday, lowering of the west end Saturday: Nearly complete demolition Sunday: Demolition of the existing east abutment cap   • Precast abutment construction   Heavy lifts Setting of the new precast east abutment cap Sunday: Trackwork required for the roll-in New bridge rolled half distance   Examples of other ABC Projects NICTD Bridge over Torrence Avenue, Chicago 2013–Roll-in 65′ thru-girder span over Trail Creek, Michigan City Build new abutments behind existing Case Study of Copano Bay Bridge, TX   Carries SR 35-Gulf Intracoastal Waterway 11,010 ft long, 129 ft wide, 75 ft tall Main navigational structure–CIP pile caps, tall columns, and bent caps Kraemer’s ABC experience includes:   • Innovative construction methods including • Incremental launching • Superstructure roll-in 6.11  Curved girders instability in unbraced erection conditions 299 FIGURE 6.11 CNR Rainy River Bridge Replacement, Baudette, Minnesota • Superstructure slide-in • Superstructure float-in • Prefabricated bridges and components including • Precast bent caps • Precast columns • Precast abutments • Full depth precast deck panels   Representative projects are listed in Table 6.24 Figure 6.11 shows the use of floating platforms for Rainy River Bridge in Minnesota Construction over rivers is more difficult than over intersections Elevation of floating platforms is governed by high tides and high winds Deep foundations like driving piles in the river bed may require cofferdams or river diversion 6.11  Curved girders instability in unbraced erection conditions Traditionally, design engineers and contractors work independently in the design and construction of most bridges Design engineers are generally responsible for making sure the bridge is able to withstand all strength and service limit states in the end configuration while contractors are generally responsible for the stability of the bridge during erection and construction and to make sure the bridge is constructed as specified by the designer Curved girders are asymmetric in plan Curved I-girders are subjected to various loading and support conditions throughout the different stages of construction The lack of cross-bracings with unassembled curved girders causes warping stress from torsion even before the bridge is used The torsionally induced warping stresses in horizontally curved girders can often equal or exceed the girder’s bending stresses Such girders are susceptible to both local and global buckling modes Global 300 CHAPTER 6  Rapid Bridge Insertions Following Failures buckling modes often control due to the limited availability of bracing during the early stages of construction Because of the limited bracing, the bridge system has significantly less torsional stiffness and will rotate more The larger unbraced length also makes the bridge more susceptible to lateral-torsional buckling Highly curved bridges may experience relatively large warping stresses as a result of the large torsional moment Overdesigned procedure can be avoided if prefabricated composite girders, either partially or fully assembled, are used to help overcome the erection stresses For lifting, an optimum use of both holding cranes and shore towers needs to be investigated Additional high-capacity cranes should be used, as the composite girder assembly will be heavier A study was sponsored by the Texas Department of Transportation at the University of Texas, at Austin, resulting in publication of “Guidance for Erection and Construction of Curved I-Girder Bridges” in 2010 by the researchers Jason Smith et al The study showed the following deficiencies with the nonassembled erection and noncomposite stages of deck slab construction: All erection stages should be analyzed for excessive deformations, stresses, and buckling considerations The concrete deck placement produces a large load on the bridge before full composite action can be accounted for and the stabilizing effects of the hardened deck can be achieved Thus, each concrete stage should be analyzed for excessive deformations, stresses, and buckling considerations Many contractors use rules of thumb and experience to ensure stability during erection Rules of thumb differ from one contractor to another, and consistent erection methods are a rarity Although some rules of thumb may be quite conservative, others may be much less so Therefore, coming up with design guidelines based on parametric studies rather than rules of thumb are desirable to help allow the contractor and the designer to work together to prevent issues that may occur due to the lack of communication between the two professions Temporary supports are very expensive because they can require significant efforts to construct and often occupy valuable space that may interfere with traffic flow around the construction site Cases where a holding crane may be satisfactory over a shore tower are also not well understood To improve the understanding of temporary support requirements, the three-dimensional Finite Element Analysis (FEA) models must be validated using stress and rotation 6.11.1  Use of commercial computer software to analyze erection stress A comparative study of erection stresses (such as those due to warping) encountered during the different processes of erection can be made between the conventional and the ABC prefabricated and preassembled methods The latter method is likely to show lower stresses In addition to the theoretical analysis, strain gauges need to be mounted on the flanges and webs of curved girders to measure stress distributions To compare different analysis programs, Nevling et al (2006) utilized the results from a field study on a three-span curved bridge with five girders For manual analysis, a line girder method of analysis from the AASHTO (1993) Guide Specification for Horizontally Curved Highway Bridges and the V-load method are used V-load method: This is one of the first analytical methods used to design curved girders and was introduced by U.S Steel in 1963 (Richardson, Gordon, and Associates 1963) This method was investigated by Fiechtl et al (1987), and they presented a report on the development and evaluation of the 6.11  Curved girders instability in unbraced erection conditions 301 method The V-load method accounts for the girder curvature by applying self-equilibrating vertical loads on the girder The report by Fiechtl et al compares these results with refined finite element analysis for a variety of bridge configurations 2D grillage models: The V-load method is accurate for noncomposite sections, but did not perform well for composite action due to the shear transfer by the deck The following 2D grillage models are useful for design calculations of various load cases of the completed structure:   • MDX • DESCUS • SAP2000   However, the 2D models are not capable of analyzing the girders during construction and can miss critical information that can only be obtained from a full 3D analysis 3D finite element programs: There are several programs available:   • ANSYS • ABAQUS • LUSAS • ADINA • BSDI   UT Bridge for construction loads: UT Bridge is a user-friendly 3D finite element program that can be used to analyze partially constructed bridges and to provide valuable information to engineers and contractors in the assessment of the safety of a bridge at various construction phases These 3D packages not include predefined load cases or the AASHTO checks 6.11.2  Modeling methods T  he finite-element method is one of the most general and accurate methods, but requires a significant amount of time to implement The finite-strip method divides the bridge into narrow strips with radial supports and provides some simplicity over the finite-element method, but does not offer the same flexibility as the finite-element method The finite-difference method superimposes a grid on the structure, and the governing differential equations are replaced by algebraic difference equations and solved at the grid points The slope-deflection method establishes partial differential equations in terms of the slopedeflection equations and is solved assuming a Fourier series   The finite-element method is the most flexible with respect to configurations and boundary conditions Computer FEM modeling can be completed with the incorporated graphical interfaces and can expedite the results Lifting and erection should be avoided in windy conditions or when there is a high temperature change Lifting and erection loads analysis: The computer analysis for temporary loads can be more complex than the regular analysis for long term live loads Since the construction method used by each contractor is different, temporary load analysis cannot be laid down in advance 302 CHAPTER 6  Rapid Bridge Insertions Following Failures The contractor needs to have the analysis method pre-approved by both the consultant and the owner to avoid any mishap in the field 6.11.3  Stresses during girder lifting Three of the critical issues that need to be addressed by the engineer when considering the lifting of girders are buckling, deformations, and stresses Although local buckling of plate elements needs to be considered during construction, most I-girders with practical proportions are usually controlled by lateral-torsional buckling A linear buckling analysis can be used to determine the critical buckling load, but the analysis is applicable for problems with small prebuckling deformations Except for extremely slender girders, yielding is not usually a problem unless the girders experience excessive deformations However, the stress calculations should include both strong and weak axis bending as well as warping normal stresses from the torque applied Descriptions of the spreadsheet calculations as well as the assumptions made during its development are incorporated into an Excel spreadsheet program named UT Lift 6.11.4  Erection practices for lifting horizontally curved I-girder: Typical lifting scenario Shore tower supporting curved girders with pier (spreader beam is being mounted for lifting of adjacent girder) Construction issues: The length of a girder segment is most often controlled by the transportation hauling length The maximum single girder segment lifted is 150 feet The size of the pieces lifted depends on the lengths that can be transported to the site, the size of the crane available, and the bending stresses that can be tolerated without buckling For continuous units, falsework must be used to support one girder as the other is lifted for splicing The first lift should preferably be a pair of girders Single or double crane lifts require cranes over 250-ton capacity, which would increase the cost of the erection Shore towers and holding cranes: The primary function of a shore tower or holding crane is to reduce deflections and stresses as well as provide stability to the girder prior to full assembly A shore tower is a structure that is placed at a specific location along the girder to provide a reaction on the bottom flange A shore tower can provide restraint to the system in all of the translational directions Use of spreader beams: The use of other lifting devices such as slings would not allow the beam clamps to hang vertical, which could cause them to slip or cause excessive flange deformation when the girder is lifted; the girder could also roll The use of adjustable spreader beams is preferred The maximum reported spreader beam length is 150 feet However, the length based on the lateral torsional bending stress limit is given by AASHTO Cranes: It is more desirable to use one crane only and a spreader bar for curved I-girder erection Contractors typically prefer the use of one crane due to the high cost of renting this type of heavy construction equipment Determining lifting points: The lifting locations are determined through structural analysis Unbraced flange length, compression flange stresses, and the ability of the top flange to sustain load transfer to the beam clamps are some of the engineered requirements A two-point lift is preferable to eliminate the “roll.” 6.11  Curved girders instability in unbraced erection conditions 303 Shoring: The high cost of installing and designing temporary falsework to support curved I-girders during erection is important The premature removal of temporary shore towers, improperly locating falsework, and lack of falsework adversely affects the structural system Erection: The effect of splice locations pertains to girder erection The first girder that is in a set requires a holding crane or shore tower to temporarily support it until the adjacent girder is erected Such an idea is ideal for design-build contracts, because the design engineer must know the methods and means that will be used to erect the girders while designing the superstructure of the bridge Unbraced length: Design specifications lack in-depth criteria for horizontally curved I-girder lifting The equation in the AASHTO LRFD Bridge Design Specifications (2007) should be used Use of a parametric finite element model: To understand the behavior of curved girders during lifting, it is desirable to perform a series of analyses with a wide range of parameters to improve the understanding of the girders over a range of support and loading conditions The parametric study can be carried out using the powerful finite element analysis software, ANSYS The variables in the parametric study include the radius of curvature (R), flange width to depth (bf/D), length to depth (L/D), and lift point location (a/L) 6.11.5  Review of AASHTO LRFD bridge design specification (2007) and other key specifications There are several bridge design codes that specify requirements for curved I-girders during construction The following paragraphs discuss the stated requirements of several codes and include the preferred practices for the state of Texas   Section 2.5.3 discusses the design objectives during construction “Constructibility issues should include, but not be limited to, consideration of deflection, strength of steel and concrete, and stability during critical stages of construction.” Chapter is dedicated to the structural analysis of bridges, and Section C 4.6.1.2.1 states: “Bracing members are considered primary members in curved bridges since they transmit forces necessary to provide equilibrium.” “Curved I-girders are prone to deflect laterally when the girders are insufficiently braced during erection This behavior may not be well recognized by small-deflection theory Classical methods of analysis usually are based on strength of materials assumptions that not recognize cross-section deformation Finite element analyses that model the actual cross-section shape of the I-girders can recognize cross-section distortion and its effect on structural behavior.” The recommendation of using finite-element analysis to model the bridge cross-section and bracing members is accomplished by the UT Bridge program Chapter discusses the design of steel bridges Section 6.5.1 states that the limit states should be investigated “for each stage that may be critical during construction, handling, transportation, and erection.” Section 6.7.4.2 discusses specific limitations on the unbraced length of curved I-girder bridges The AASHTO LRFD Bridge Construction Specifications (2004) provide the required construction practices as stated by AASHTO Section 11.6 discusses the erection of steel structures, and states in Section 11.6.4.3 that “Cross frames and diagonal bracing shall be installed to provide 304 CHAPTER 6  Rapid Bridge Insertions Following Failures stability and ensure correct geometry Temporary bracing, if necessary at any stage of erection, shall be provided by the Contractor.” The AASHTO/NSBA Steel Bridge Erection Guide Specification (2007) is published jointly by AASHTO and the National Steel Bridge Alliance (NSBA) Chapter of this document specifically discusses erection procedure, and requires that a contractor provide a detailed erection procedure to the owner prior to the start of construction Section 2.3(b) states that submitted procedures should contain “calculations to substantiate structural adequacy and stability of girders for each step of bridge assembly.” Chapter discusses the lifting procedure and states that “crane and materials must be located such that the lift is safe and within the crane manufacture’s capacity.” Also, Section 6.3 states that “Girders shall be stabilized with falsework, temporary bracing, and/or holding cranes until a sufficient number of adjacent girders are erected with diaphragms and/or cross frames connected to provide the necessary lateral stability and to make the structure self-supporting.” The commentary associated with Section 6.3 states that “Removal of falsework, temporary bracing, and holding cranes shall be in accordance with stability provided in the erection procedure.” Section 2.2.1 states that “for curved girders, flange width should be approximately one-third the web depth and no less than 30 percent of the web depth The extra width for curved girders enhances handling stability and helps keep lateral bending stresses within reason.” The Preferred Practices also state that “flange width affects girder stability during handling, erection, and deck placement Keep the girder length (field section length) to flange width ratio below 85.” Section 2.2.4 provides additional cross-sectional proportioning recommendations and states that the recommended depth given in AASHTO 2.5.2.6.3 should be increased by 10–20% for curved girders According to the TxDOT Preferred Practices, the total superstructure depth to span length ratio should be (1:0.033–1:0.04) Section 2.6 states that for curved girders, TxDOT prefers that diaphragms or cross-frames be placed at 15–20 feet maximum to help limit flange-bending stresses and cross- frame/diaphragm member forces 10 Another source of information about the current state of practice in construction and erection of curved I-girder is the NCHRP Synthesis 345 report (2005) This report, titled Steel Bridge Erection Practices: A Synthesis of Highway Practices, documents a survey sent to state departments of transportation, contractors, and fabricators   Top flange bracing: Structural analysis should be performed to make sure that the girder does not translate a significant amount when the lifting crane is released Bridge Construction Equipment: NRS AS is a Norwegian company, which deals with advanced construction equipment for concrete bridges and modern techniques of construction (Reference Oslo, ­Norway, nrs@nrsas.com) It provides exhaustive coverage of new and emerging bridge construction technology and modern construction methods for all bridge professionals looking to save time, labor, and costs, reduce risk, and increase the value and quality of bridge projects through mechanized construction Bridge construction equipment is becoming increasingly more complex and sophisticated The book explores configurations, operations, kinematics, performance, productivity, structure–equipment interaction, and industry trends for every family of special equipment Each chapter also includes coverage of deck fabrication Design-oriented chapters provide guidance on prevention of human error, design for robustness and 6.12  Costs of bridge failures and funding allocations 305 redundancy, modeling and numerical analysis, instability and prevention of progressive collapse, and repairs and reconditioning of second-hand machines Management-oriented chapters describe procurement, fabrication, and commissioning of special equipment 6.12  Costs of bridge failures and funding allocations 6.12.1  Transportation funding and financing The Federal Aid Highway Act of 1956 is responsible for highway funding The official funding policy stated by Anthony Foxx, the 17th U.S Secretary of Transportation, is as follows: “Governors and states have long recognized the importance of investing in surface transportation When operated efficiently, the surface transportation system can enhance the economic competitiveness of states and the nation, as well as increase safety and the quality of life for users.” However, the nation’s transportation system faces many pressures, including a growing imbalance between system use and capacity, the erosion of traditional funding sources, increasing costs for the construction and maintenance of infrastructure, and shrinking sources of credit during difficult economic times States are exploring a variety of new and innovative funding and financing methods, while at the same time looking to maximize the effectiveness of traditional sources NGA Center activities: To help states with transportation funding and financing issues and challenges, the NGA Center monitors and evaluates funding and financing challenges and policy responses across the states, and disseminates information through publications, conferences, and workshops to accelerate the adoption of the most effective policy tools and best practices It provides governors and their policy advisors with targeted research and analysis on existing financial mechanisms as well as innovative new tools The NGA Center has also assisted states in exploring several funding and financing options, including debt financing (state infrastructure banks), a variety of user fees, public–private partnerships, and strategies specifically designed for freight The available NGA Center Resources need to be consulted 6.12.2  Essential costs of failures and the use of ABC When the highway is shut down, it results in long detours, lowering of the speed limits, traffic jams, closing down of some local businesses, plus the loss of time for reconstruction A projected cost estimate in millions of dollars may be made In the ASCE Reston, Virgina Waterforum of 1992, Kenneth Young proposed guidelines of costs of sudden and unexpected requirements of each disaster These may be modified as follows: Total direct costs = Demolition costs + New construction costs = C1 L.W + C2 L.W = (C1 + C2) L.W where   C1 = Unit cost of demolition and disposal of damaged bridge L  = Length of new bridge W = Width of new bridge C2 = Unit cost of new bridge   306 CHAPTER 6  Rapid Bridge Insertions Following Failures An estimate of indirect costs should include any extreme weather conditions affecting construction, any unforeseen delays or shut-downs due to non-availability of materials, strike etc These costs can be absorbed in insurances if it is in effect Total indirect costs during construction = Daily cost of detour length + Cost of time loss = C3 D × A × d + [C4 × O (1 − T/100) + C5 T/100] (D × A × d) /S = C3 + [C4 × O (1 − T/100) + C5 T/100] /S (D × A × d) where   C3 = Unit cost of running a vehicle per mile ($0.50–$0.60) D  = Detour length in miles A  = ADT based on earlier traffic count d   = Duration of detour in days C4 = Value of time per adult ($10–$15 per hour) O  = Average occupancy rate per vehicle (1.25–1.5) T   = ADTT percentage C5  = Value of time per truck ($20–$30 per hour) S  = Average detour speed (30–50 mph)   Each item for each bridge requires an individual cost evaluation based upon bridge data, location, and unit cost of the type of construction, detour length, etc., and costs will vary for each state An Excel spreadsheet is required, as some costs will be based on bid items submitted by the selected contractor By using ABC modular bridges and design-build contracts, the durations of demolition and new construction can be significantly reduced It will lower the costs that are being incurred in conventional construction Funding for unforeseen failures is not easily available FHWA has an Emergency Relief Fund while FEMA has a Disaster Assistance Program (DAP) The funds provided are never enough For example, in the 1985 floods that struck the states of West Virginia, Virginia, Maryland, and Pennsylvania, nearly 50 bridges were lost At an average, if $2 million are required to repair each damaged highway and the bridge, it will require $100 million The DAP and ERF were able to provide $55 million The deficit needs to come from the state funds, and usually are increased by raising gasoline taxes Future maintenance costs are not included 6.13 Conclusions Failure studies: A survey at the international level was conducted to identify the reasons for failures in using conventional methods Maintenance can avoid failures and at least warn of trouble in advance Use of remote sensors to monitor structural health is desirable Early failures in conventional construction can be attributed to a variety of reasons, both administrative and technical The study shows failures resulting from inadequate overseeing of projects, a lack of supervision at the site, design errors, lack of comprehensive codes, limited resources, and contractors’ last-minute decisions to meet hasty schedules For example, it is not easy to provide a 6.13  Conclusions 307 large number of temporary supports in one construction phase, which may result in support settlement and collapse Most of the failures occurred during construction due to lack of redundancy in design, inadequate construction, and lack of contracting experience and knowhow Bridges on rivers failed more than on the intersections, due to soil erosion Use of HEC-23 countermeasures is on the rise Keeping the number of piers to a minimum will save costs Balance cantilevers are required in segmental construction, as the use of temporary supports may not be possible Some progress has been made in making bridges seismic-resistant by using lightweight materials and isolation bearings Failures are not specific to any structural system Steel girder bridges are as popular as trusses depending upon the span lengths However, construction of curved girder bridges is more difficult than those of skew or straight bridges Use of modern technology: Bridge engineering is changing with time New technology and innovative ideas developed in the last 20 years need to be adopted In planning bridges, cost is still the main criterion Much of the cost goes in the foundation and substructure concrete construction The use of new and stronger construction materials such as HPS, HPC, Ultra HPC, and FRP decks should be encouraged, as these are more durable Shallow-depth girders will result, which are lighter in weight Galvanizing will reduce corrosion Currently, rolled sections in HPS 70 and 100 W are not available or expensive Welded girders in HPS are being used Prestressed concrete box girders are stronger in torsion and cost-effective, especially with the use of lightweight concrete and lower maintenance costs Also, composite construction such as using the inverse system is more economical and on the rise Precast integral abutment construction requires greater attention Minimize cast-in-place concreting on-site: The closure joints on the deck between precast panels require wet concrete up to two feet wide Ultra HPC and high early-strength admixtures may be used Project management and quality control: MPT is of critical importance Quality control is another difficulty Project managers at highway agencies may be encumbered with many bridge replacements at a given time and not have enough time to deal adequately with the contractor’s claims and many change orders simultaneously Consultants are supposed to serve as their right hand, but it may not always work that way Adequate liability insurance needs to be taken out for unforeseen items so that the owner (and eventually the taxpayer) is not penalized by cost increases Modular transporters and construction devices: ABC prefabrication and preassembly of bridge components, and the use of SMPTs and high-capacity cranes, can and should prevent at least the construction failures FHWA has published an informative manual on use of SMPTs to remove and replace bridges (refer to Publication No FHWA-HIF-07-022, dated June 2007) Similar manuals exist for lifting cranes, whether manufactured in United States or abroad, and include their effective boom lengths and related capacities Girder supports need to be identified and also whether one or two cranes are being used Peak stress and deformation can be checked prior to lifting The location of cranes needs to be identified on contract drawings Improving team performance: It was observed that the professional relationship between the owners, contractors, and consultants needs improvement through increased communication ABC designbuild methods are a step in the right direction Profit margins in contracting can vary in each state and in each country Sometimes these relationships can turn sour when big money is involved Fabricators need to come up with better details for connections and splices Shop drawing standards are required 308 CHAPTER 6  Rapid Bridge Insertions Following Failures Training in prefabrication and preassembled bridges and erection methods needs to be provided to design and construction engineers so that ABC can be implemented at a rapid pace Upgrading design specifications: New design codes and construction specifications related to precasting need to be developed New AASHTO specifications using ABC methods are required LRFD methods will still be required These may include a finite-element 3D analysis for erection conditions Existing computer software can include analysis and design based on construction load combinations Widening of highways in urban areas is not always an option Right-of-way and legal issues are involved to acquire new land Hence underpasses and/or double-deck highway will overcome the additional lanes problem and traffic congestion once and for all Bridges on rivers: Chapter 11 also addresses the issues linked to ABC Deep foundations are preferred over shallow foundations for bridges that are scour-critical Scour countermeasures need to be designed according to HEC-23 and provided to protect footings When replacing an existing superstructure, deck elevation may be raised by one to two feet Training needs: Training of construction personnel in ABC techniques is therefore desirable as addressed in Chapter A greater number of bridges are now being built using ABC Websites such as FIU, FUWA, and the local Department of Transportation research library will be useful Safety checklists: Construction safety at sites requires the personnel to be safe and healthy A checklist of do’s and don’ts needs to be prepared and issued NOTE: Bibliography for this chapter is listed at the end of the chapters in Appendix A list of Bridge Inspection Terminology and Sufficiency Ratings used by PennDOT is given in Appendix ... 868 2 7318 568 0 Construction related Construction related Construction related Use prefabrication Use design-build management Implement OSHA regulations 266 CHAPTER 6 Rapid Bridge Insertions Following. .. type of drawbridge ABC 2 86 CHAPTER 6 Rapid Bridge Insertions Following Failures FIGURE 6. 6 SR 520 over Lake Washington, Seattle Table 6. 21  Categories of Estimated Number of Bridge Failures Category... chord, cantilevered construction 2 76 CHAPTER 6 Rapid Bridge Insertions Following Failures Conclusions: This is a design issue related to construction Long-span bridges involve construction in cantilever